Stereomicroscope variable focus mounting



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Oct. 30, 1962 o. w. BoUGHToN ETAL 3,060,801

STEREOMICROSCOPE VARIABLE FOCUS MOUNTING TQM? 7 Original Filed April 2l.1958 3 Sheets-Sheet l OLIN W. BOUGHTON KENNETH D. MAIER 1N VENTORSATTORNEY Oct. 30, 1962 o. w. BouGHToN ETAL 3,060,801

sTEREoMIcRoscoPE VARIABLE Focus MOUNTING Original F'iled April 2l, 19583 Sheets-Sheet 2 N s am L HMN GMW Q U 1 OD uw d Wm A um OK m ATTORNEYOct. 30, 1962 o. w. BouGHToN ErAL 3,060,801

STEREOMICROSCOPE VARIABLE FOCUS MOUNTING 3 Sheets-Sheet 3 Original FiledApril 2l, 1958 OLIN W. BOUGH TON KENNETH D. MAIER INVENTORS 8521.4 @JQ-aATTORNEY United States Patent() M 3,060,801 STEREOMICROSCOPE VARIABLEFOCUS MOUNTING Olin W. Boughton, Canandaigua, and Kenneth D. Maier,

Meudon, N.Y., assignors to Bausch & Lomb Incorporated, a corporation ofNew York Original application Apr. 21, 1958, Ser. No. 729,782, nowPatent No. 2,942,519, dated June 28, 1960. Divided and this applicationOct. 5, 1959, Ser. No. 848,487

4 Claims. (Cl. 538-39) This invention relates to microscopes and moreparticularly to a casing and mounting structure for a stereoscopicbinocular microscope having means for continuously varying themagnification of the optical elements housed therein. The presentinvention is particularly adapted for housing and mounting thestereomicroscope lens system disclosed and claimed in the copendingapplication Serial No. 729,800, tiled April 21, 1958 and assigned to thesame assignee, now abandoned. This application is a division of ourcopending application Serial No. 729.782, tiled April 21, 1958, nowPatent No. 2,942,519 issued June 28, 1960.

The principal object of the present invention is to provide an improvedstereomicroscope casing and mounting structure which is adapted to housea continuously variable magnification objective lens system whereby theobjective lens elements may be easily and accurately moved within theirlimits. Another object of .this invention is to provide an improvedmounting for the objective lens elements such that they may be moved insynchronism along prescribed paths.

Another object of the invention is to provide a mounting structure forthe binocular mirror arrangement and the objective lens system of thetype that provides for continuous variable magnification which willpermit unit assembling of the microscope components and easy removal oradjustments of the individual components of the subassemblies.

Other objects and advantages will become apparent from the followingdescription taken in conjunction with the drawing, wherein:

FIG. 1 is an elevational view, partly in section, of a stereomicroscopeembodying the principles of the present invention;

FIG. 2 is a vertical sectional view through the mirror and objectivehousings of the present invention;

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 3; and

FIG. 5 is a blow-up of the casing and mounting structure for the mirrorand objective lens system.

Referring now to the drawings and particularly to FIG. l, there is showna binocular stereomicroscope body or head comprising a mirror casing 12having its lower side open and exposed to the open upper side of anobjective casing 14 detachably mounted thereto in telescoping fashion bymeans of bolts 16. Mounted on top of the mirror casing is an ocularsystem comprising binocular eyepieces 18, either of which may beindividually adjustable both for focus and interpupillary distance. Thehead 10 is adjustably secured to a stand 22, by a suitable adjustmentmeans (not shown) for vertical movements to facilitate the positioningof the optical system with reference to an object plane 24. A

conventional base and substage may be incorporated into the illustratedmicroscope and since these parts do not form a part of the presentinvention, further description thereof is unnecessary.

The objective lens system includes two sets of lens elements, each setcomprising elements 26, 28, 30 and 32, 34, 36, respectively, and havingcorresponding optical 3,060,801 Patented Oct. 30, 1962 axes 38, 40 whichare inclined with one another so as to converge at a point on the objectplane 24. The characteristics and properties of the lens elements 26,28, 30 and 32, 34, 36 form no part of the present invention as these aredisclosed and claimed in the above-referred to copending application.However, the various functions and positionings of the objective lenselements which are identical to that disclosed in the said applicationswill be discussed briefly in order to point out the various novelfeatures of the present invention.

The lens elements 26 and 32 are held stationary with respect to theobject plane 24 and as shown in FIGS. 1 and 3 are suitably encased insleeves 42, only one of which is shown mounted at the lower end of ahousing 44. The lens elements 28, 30 and 34, 36 are slidably mountedwithin the housing 44 wherein elements 28 and 34 are movable in unisonat one rate of non-linear movement and elements 30 and 36 are movable atanother rate of non-linear movement along the optical axes 38 and 40,respectively, as will be presently described.

The housing 44 is in the form of a box-like structure having a slightlytapering body 46 and an outwardly extending flange 48 along the top edgethereof. This ange is formed with openings 50 for allowing the passageof a plurality of screws 52 therethrough which are adapted to bereceived in corresponding tapped bores formed on support shoulders 54 ofthe objective casing 14. In this manner, the housing 44 may be easilyremoved from the the microscope body 10 by first detaching the mirrorcasing 12 from the body in order to expose the interior of the objectivehousing, and then removing the screws 52 so that the housing 44 may beeasily lifted from its support position on the shoulders 54.

The bottom wall 56 of the housing 44 is opened to permit the mounting ofthe sleeves 42 by a plurality of bolts 57 for the lens elements 26 and32. As shown in FIGS. 3 and 5, the housing 44 is fully open at the topin the plane of the flange 48 and at one side. A stirrup or yoke 58formed integral with the housing 44 rises above the same and spansacross the top thereof. A pair of bores 60 are tapped in flat bosses 62on the yoke and arc spaced equally on either side of the center plane Aof the housing (see FIG. 2). An extension plate 64 integral with theyoke 58 has a large aperture 66 formed therein with the center thereofin line with the center plane A of the housing 44 and equidistant fromthe centers of the bores 60. Another stirrup or yoke 68, mounted on theflange 48 by screws 70, also rises above the housing and bridges acrossthe open top thereof slightly higher than the yoke 58 and approximatelyin the vertical plane thereof.

The yoke 68 has an extension plate 72 integral therewith and extendingin a direction opposite to that of the plate 64. Angularly dependingfrom the plate 72 is a projection 74 which supports a flat plate 76having a top surface parallel to the top surface of the plate 72, butspaced therefrom. A pair of tapped bores 78 are formed in the plate 72,equidistant from the transverse center line thereof and a pair of tappedbores 80 are formed in the plate 76, also at points equidistant from thetransverse center line of the plate 76.

The yoke 68 and the plates 72, 76 serve as a support for a mirror andeyepiece mounting frame indicated generally by the reference numeral 82.The mounting frame S2 comprises two similar brackets 84, 86 each ofwhich is formed with an eyepiece mounting nipple 88,

i 90, respectively, which support the eyepieces 18, 20.

Means are provided for pivotally mounting each of the brackets 84, 86upon the plate 72 and to this end, an opening 92 is formed on thebracket 84 for receiving a pivot pin 94 which is in threaded engagementwith one of the bores 78 on the plate 72. A head 96 on the other end ofthe pin 94 serves to prevent lifting of the bracket when the pin 94 islocked to the plate 72. Similarly, the bracket 86 is formed with anopening 98 for receiving a pivot pin 100 which is in threaded engagementwith the other bore 78. A head 102 on the pin 100 retains the bracket 86upon the plate 72. The clearance between the heads 96 and 102 and theirrespective brackets is such as to permit easy pivotal movement of thebrackets.

In order to insure equal pivotal movement of the brackets 84, 86, asimple linkage is provided thercbetween for imparting any motion of onebracket to the other. The linkage comprises a rocking lever 104 formedintegral with the bracket 84 and a notch 196 formed in an extension 108of the bracket 86. A circular bearing tip 110 at the extreme end of thelever 104 is retained within the notch 106 and is adapted to ride alongthe edges thereof upon rocking movement of the brackets 84, 86 abouttheir respective pivots 94, 100.,

Pivotal movement of the brackets serves to vary the distance between thecenters of the eyepiece nipples 88, 90 and consequently the distancesbetween the optical axes of the eyepieces 18, thereby providing a simplemeans for adjusting or presetting these distances. In order to maintainthe nipples 88, 90 and consequently the brackets in any desired positionto which they have been moved, a pair of slots 112, one formed on anextension 114 on each of the brackets 84, 86, is provided. These slotshave extending therethrough bearing screws 115 which are in threadedengagement with the bores 80 in the plate 76 and are formed with bearingsurfaces 116 which engage the edges of the slots and thereby releasablyhold the extensions 114 in place. The extensions 114 are adapted toslide on the plate 76 during pivotal movement of the brackets 84, 86 andmay be maintained in any desired position by the engagement of thesurfaces 116 with the edges of the slots 115 when a proper distancebetween the eyepiece nipples 88, 90 has been obtained. In actualpractice, movement of the eyepieces 18, 20 will effect the movement ofthe nipples 88, 90 and the brackets without necessitating removal of thecasing 12 from the microscope body 10.

Each of the brackets supports a mirror arrangement, indicated generallyat 117, for transmitting the image of an object to the respectiveeyepiece. Instead of mirrors, prisms may be utilized to effect the samepurpose. Since these reflective arrangements are well known in the art,it will be unnecessary to describe the details and operation thereof.The mirror arrangements serve to fold the image forming rays emanatingfrom the object plane 24 and direct the same along the optical axes ofthe eyepieces 18, 20 and since these mirror arrangements are movablewith the brackets 84, 86, the image rays will be so directed for anyposition of the eyepiece nipples 88, 90 within their limits of movementas defined by the length of the slots 112. It will be obvious that themirror arrangements 117, the brackets 84, 86 and the structure supportedthereby are contained in the mirror casing 12, so that upon removal ofthe casing, the above structure will be exposed for easy removal,adjustment or the replacement of parts. To detach the brackets 84, 86from the plates 72 and 76, which support the same, merely requires theremoval of the screws 96, 102 and 116. A plurality of screws 118 serveto suitably attach the individual mirrors of the mirror arrangements 117to the corresponding bracket, and screws 119 are utilized to adjust theangularity of the mirrors in order to insure alignment of the opticalaxes of the arrangements. The details and operation of the adjustingmeans (not shown) are well known in the art and need not be describedhere.

Within the housing 46 two guide rails 120, 122 are mounted adjacent awall 124 thereof and are inclined with one another at an angle equal tothe angle between the optical axes 38, 40. `As shown in FIG. 2, thelongitudinal axis of the rail 120 is parallel to the opticial axis 38,and the longitudinal axis of the rail 122 is parallel to the opticalaxis 40. Each of the rails is adjustably secured to the wall 124 by apair of screws 125, 126, respectively, which project through suitableapertures 127 in the wall. It will be noted, see FIG. 3, that theapertures 127 have a diameter slightly larger than the diameters of thescrew thus permitting slight lateral adjustment of the screws beforethey are fastened. In this manner, the rails 120, 122 may be adjustedalong their respective axes and to either side thereof in order toadjust the alignment and the parallelism of the guide rails with theoptical axes 38, 40.

Each of the rails 120, 122 serves as a guide for a pair of lens holdersto be described hereinafter, and, since both pairs of lens holders andthe corresponding driving means are identical, only one set of theseelements will be described in detail. In FIG. 3, the rail 120 is shownhaving associated therewith a lower lens holder 128 which carries thelens element 28 and an upper lens holder 129 which carries the lenselement 30. As previously mentioned, the lens elements 26, 28 and 30 arein axial alignment and along their optical axis, the lens elements 28,30 are arranged to be moved relative to one another and to the xedelement 26. The end of each of the lens holders adjacent the rail 120 isformed with a generally rectangular notch 139 having a width slightlylarger than the width of the rail for permitting the rail to freelyslide therethrough. A bearing block 131 is fixed at one side of thenotch 130 and a spring biased block 132 is provided at the other sidethereof for insuring a relatively rm engagement of these blocks upon therail. The spring force exerted upon the rail is such that the lensholder will always travel in a straight line and in a predetermined pathalong the optical axis 38 without undue friction placed upon the lensholder.

Such movement of the lens holders 128, 129 is accomplished by means of arotatable cam cylinder 134 which has its longitudinal axis parallel tothe optical axis 38. The cam cylinder is mounted at its ends within thehousing 44 by means of adjusting screws 136, 138 and a ball bearingpositioned in suitable recesses formed in each end of the cylinder andthe adjacent end of the corresponding adjusting screws. The adjustingscrew 136 is aligned axially with the cam cylinder 134 and is adjustablyretained in the end wall 56 of the housing 44. A lock nut 142 on thescrew 136 serves to lock the same with respect to the end wall when thecam cylinder is initially located in a predetermined position. At theother end of the cam cylinder, the adjusting screw 138 is aligned withthe axis of the cam cylinder and is retained in the tapped bore 60formed in the yoke 58. A lock nut 144 on the screw 138 serves to lockthe same against movement when the cam cylinder is in its desiredposition. Actually, both screws 136, 138 are utilized in order toposition the cam cylinder or to adjust the same in the event such actionis required. The ball bearings 140 serve to permit easy rotation of thecam cylinder during actuation thereof.

The lens holders 128, 129 are formed with coaxial openings 146, 148,respectively, which are adapted to slidably and rotatably receive thecam cylinder 134. In FIG. 4, the opening 146, which has the sameconfiguration as the opening 148, is shown as being dened by two facingcutouts 150, 152, one of which is formed in the lens holder and theother in an end block or cap 154 suitably attached to the holder bybolts 156. The cutout has three sides, with each of the two extremesides having a pair of upper and lower bearing blocks 158 for engagingthe cylinder 134, see FIG. 3. The other cutout 152 has three sides, ofwhich the middle side is provided with a pair of upper and lower springbiased bearing blocks 160 in spaced alignment and also contacting thecylinder 134. Thus, the lens holders are held against lateral movementrelative to the cylinder by a six bearing contact arrangement associatedwith each of the lens holders. The bias on the block 160 is such as toallow rotation of the cylinder and sliding of the lens holders withoutundue friction between all of the bearing blocks and the surface of thecylinder While at the same time restricting movement of the lens holdersalong the axis of the cylinder when the same is not rotating. Theprovision of a removable end block 154 permits easy removal oradjustment of the cylinder without aifecting the lens holders 128, 129.

In order to impart movement to the lens hol/ders 128, 129 along theoptical axis 38 of the lens elements 28, 30, each of the lens holders isprovided with a cam follower 162 which is secured to the end block 154vbetween the bearing blocks 160 and projects into the respectivecylinder receiving opening 150 or 152. The follower 162 associated withthe lens holder 128 cooperates with the edges of a non-linear helicalcam groove 164 formed in the cylinder 134 and the follower associatedwith the lens holder 129 similarly cooperates with the edges of anothernon-linear helical cam groove 166 formed in another part of thecylinder. As shown in FIG. 3, the grooves 164, 166 have different pitchangles thus causing movement of the lens holders at dilferent rates ofspeed upon rotation of the cylinder.

The grooves are not continuous and are formed for approximately 340 ofthe periphery of the cylinder with the ends of each of the grooves lyingin a line parallel with the axis of the cylinder. Thus, both camfollowers will reach the terminal points of their respective groovessimultaneously. The graphic or curvature characteristics of the grooves164, 166 are disclosed in the above-referred to application and theseare such as to drive each of the lens elements 28, 30 at a predeterminedrate in order to locate the same at predetermined positions with respectto each other and the fixed lens element 26. The helix angles of thegrooves and the characteristics of the lens elements are such as toprovide continuous variable magnification of an object to be viewedduring rotation of the cylinder 134 without requiring refocusing of theother lens system of the microscope.

Means are provided for imparting smooth and slackless rotation of bothcam cylinders 134 by a single operating knob and to this end a gear 168,17 (l is coaxially arranged at one end of each of the cylinders.Cooperating with the gears 168, 170 is a drive gear 172 arrangedtherebetween and in mesh therewith. The drive gear 172 is driven by ashaft 174 which is supported by a fitting 176 suitably bolted to theplate 64 of the yoke 58. As shown in FIG. 2, the shaft extends throughthe opening 66 of the plate 64 and has mounted on the end remote fromthe drive gear 172 a manually actuated knob 178. Rotation of this knobwill rotate the drive gear which will impart simultaneous rotation ofthe cylinders 134 in opposite directions. The curves 164 on each of thecylinders are identical but are varranged oppositely thereon in order toimpart simultaneous movement of the lens holders 129 in the samedirection. Similarly, the curves 166 on the cylinder are identical andare arranged oppositely for the same purpose.

From the foregoing description, it will be appreciated that a novelmounting structure is provided for an objective lens system of thecontinuously variable magnification type. This mounting structure is inthe form of three basic elements, namely, the housing 44, theintermediate yoke 68 and the mirror mounting frame means 82. Variouscomponents of the microscope are mounted in or upon these basic elementswhich are readily assembled or disassembled from each other. Thecomponents of the microscope associated with a particular basic elementare themselves readily accessible for mounting, removal or adjustment.Such an arrangement allows for unit replacement or assembly ofsubassemblies without requiring dismantling of the other non-affectedcomponents of the microscope.

The mounting structure also facilitates the adjustments of some of themicroscope components without undue dismantling of other components suchas, for example, the individual mirrors of the mirror assembly 117. Itwill be appreciated that these mirrors are mounted on a frame whichitself may be separated intact from the microscope casing thuseliminating the usual practice of removing the mirror from the casingitself. Once out of the casing, the mirror mounting frame may be usedfor inspecting the alignment of the mirrors and any necessaryadjustments may be made while the mirrors are attached to the frame.

The movable objective lens elements 28, 30, 34, 36 may be easilyadjusted without their removal from their mounting structure, forexample, by the provision of the guide rail adjusting screws 126, 127 orby the adjustment screws 136, 138 for the cam cylinders 134. The lensholders may be removed in the event other lens elements having differentpowers are to be utilized. In this event, other cam cylinders may beeasily incorporated for the new lens elements thereby modifying thevariable magnilication range.

lt will also be appreciated that the removable basic elements may beremoved intact from the microscope casing for inspection, cleaning andlubricating purposes. Every element and component in the apparatus isthen exposed for these purposes without affecting the positioning ofthese structures.

We claim:

l. ln a mounting mechanismlfoia stero pai; gf microscope ob'ectives ofthe continuous y variable magnifica- H--f-J-TN a.. tion ty e wherein eacobjective consists of' stationary www are opiicl'lylimd wit saidstatignary lens, d are moved axiallyrwith respect thereto to vary themagni cation/ofmvtlelrnage-o the combination of a box-like open-sidedand unitary self-rigid housing which is open at one end, an end wallwherein said stationary lens is held, said wall being formed in thehousing opposite to the open end thereof and a back wall formed oppositeto the open side, an arch-like yoke formed across said open end andjoining the sides of said housing,

a pair of drivingly interconnected cam cylinders which are rotatablymounted for like rotation at one end thereof in said yoke and at theother end thereof in said end wall in converging relation to each otherso their respective axes meet at a stationary point in the plane of saidspecimen, said cylinders each having cam means formed thereon andoperatively connected for moving said varifocal lenses along saidcylinders in a rectilinear path,

two movable lens holders wherein said two varifocal lenses are held,said holders having an end portion freely encircling one of said camcylinders for movement axially thereof,

bearing means carried by said holders and operatively located betweensaid cylinders and said end portion of the holders so as to slidinglyengage said cylinders and support the lens holders normal to saidcylinders,

a pair of guide rails fixed to said back wall and having the samemutually converging relation of their longitudinal axes as the aforesaidaxes of the cam cylinders and each rail extending parallel to one ofsaid cylinders and spaced therefrom and in cooperation with saidcylinders acting to establish said path of rectilinear motion of saidlens holders which is coincident with the axis of said stationary lens,and

a pair of parallel bearing surfaces carried by the end of the lensholders which is adjacent to said rails, said surfaces being slidablyfitted against and embracing two opposite surfaces of the rail, saidvarifocal lenses being therebyy positioned between the rails and thecylinders whereby angular movement of the lens holders about thecylinder axes is prevented and true rectilinear movement of saidvarifocal lenses in coincidence with the optical axis of said stationarylens in all focal positions thereof is provided.

2. A mounting mechanism for a stereo pair of microscope objectives asset forth in claim l wherein said bearing means comprises two axiallyaligned tandem sets of three circumferentially equally spaced bearingblocks which are seated in each said lens holder around one of saidcylinders and bear radially thereon, one tandem pair of said bearingblocks being resiliently mounted in axially spaced relation to eachother at an angular position which is substantially 180 away from saidlenses and the other two bearing blocks of each set being xedly mountedwhereby the lens holder is yieldingly maintained in a position normal tothe axes of saidl cylinders.

3. A mounting mechanism for a stereo pair of microscope objectives asset forth in claim 2, said combination further including two helix-likecam grooves formed in axially spaced relation in each of said cylinders,a cam f t s follower engaging each of said grooves and seated in therespective lens holders substantially midway between the aforesaid pairof resiliently mounted bearing blocks and in alignment therewith wherebytilting of the holders out of normal position during travel in eitherdirection is minimized.

4. A mounting mechanism for a stereo pair of microscope objectives asset forth in claim 3, said combina-l tion further including a pivotmember operatively engaged at each end of all of said cam cylinders torotatably mount said cylinders, each said member being coaxially alignedwith said cylinders and being axially adjustably held in said housingfor changing axial position of one of said cylinders relative to theother.

References Cited in the le of this patent UNITED STATES PATENTS1,167,425 Ott Jan. 1l, 1916 2,093,605 Gallasch et al. Sept. 21, 19372,165,341 Capstaff et al. July 11, 1939 2,791,937 Leitz et al May 14,1957 FOREIGN PATENTS 99,849 Germany Nov. 3, 1898

